Oil for Toyota 1MZ-FE sludge engine?

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Hello

I have a 2000 Lexus RX300 with 310k miles.

The engine is the 1MZ-FE engine that is known for sludge and I bet I have a fair amount of sludge by now. I am afraid to pull the rear valve cover.

I switched to full synthetic about 4 years ago and run 5W30.

I consume about 1 quart every 500 miles. I have some small oil leaks (valve cover gaskets as well as crank or cam seals). But I think I am burning most of what I am consuming unless the oil loss is going to sludge buildup.

Should I stick with 5W30 or go up or down a grade. From a sludge point of view is thinner or thicker oil better?
 
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With your oil consumption of one quart every 500 miles, it probably won't matter. I would just use whatever oil is on sale (ie most economical).
 

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If you do indeed have ring pack sticking, Valvoline Premium Blue Restore is designed specifically to help deal with that issue (though for OTR trucks, not cars, but I have no reason to suspect it being significantly less effective in automotive applications).
 
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Seems like you're speculating right now on the consumption/sludge situation.
Pull the front valve cover and inspect (its easy).
Based in that inspection, develop an action plan from there.
 

tiredguy

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Seems like you're speculating right now on the consumption/sludge situation.
Pull the front valve cover and inspect (its easy).
Based in that inspection, develop an action plan from there.
yes that is a good plan... however I heard that the rear valve cover is the one that has many many many times more sludge under it
 

tiredguy

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With your oil consumption of one quart every 500 miles, it probably won't matter. I would just use whatever oil is on sale (ie most economical).
assuming the prices are the same should I stick with 5W30 or go up or down a grade?
 
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yes that is a good plan... however I heard that the rear valve cover is the one that has many many many times more sludge under it
So are you saying that that sludge won't migrate to other parts of the engine?
Sometimes you gotta work with what you got man....
Pull the front valve cover and inspect. It will give you an idea of the situation.

Or, just continue to speculate......

Good luck!!!
 

tiredguy

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So are you saying that that sludge won't migrate to other parts of the engine?
Sometimes you gotta work with what you got man....
Pull the front valve cover and inspect. It will give you an idea of the situation.

Or, just continue to speculate......

Good luck!!!
based on three different friends with the same engine and what I have read online the front is usually not that bad but the back is where all the big trouble is.... so a bit of speculation based on the historic trends for this engine.
 
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based on three different friends with the same engine and what I have read online the front is usually not that bad but the back is where all the big trouble is.... so a bit of speculation based on the historic trends for this engine.
Yes, speculation at its best.

If you pull the front VC and it looks ok, then you may conclude sludging isn't an issue or you may decide additional investigation is required.

If you're unsatisfied with what you think the front VC will show then pull the rear VC. Owners typically avoid this because it's a PITA on this engine. And you might as well do the spark plugs while you're back there too.

If you're unsatisfied with what you think the front VC will show then pull the rear VC. Owners typically avoid this because it's a PITA on this engine. And you might as well do the spark plugs while you're back there too.
 
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tiredguy

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Yes, speculation at its best.

If you're unsatisfied with what you think the front VC will show then pull the rear VC. Owners typically avoid this because it's a PITA on this engine. And you might as well do the spark plugs while you're back there too.
yes, bought spark plugs, plenum gasket , valve cover gaskets and a spark plug tube seals.... I may need a few bags of rags to clean out the sludge. A friend who did this job went through two cases of brake cleaner and a bunch of wire brushes and scrapers cleaning out the sludge in the rear head. He said he spent an entire day just on the rear head for sludge after he had everything removed.

He said if he had to do it again he would take some tarps and masking things off and take a pressure power washer and blast all the sludge out.
 
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I consume about 1 quart every 500 miles. I have some small oil leaks (valve cover gaskets as well as crank or cam seals). But I think I am burning most of what I am consuming unless the oil loss is going to sludge buildup.

Should I stick with 5W30 or go up or down a grade. From a sludge point of view is thinner or thicker oil better?
I've operated my old 1MZ-FE for 22 years and nearly 450,000 miles now. If you are consuming one quart per 500 miles then your choice of grade is the least of your worries. Having said that going down a grade makes zero sense whatsoever.

Open up the rear cylinder bank as you've described. If there is a problem with sludge it will be there. Until you do that nothing anyone on here says makes no difference, assess the situation and move from there.

You say you've had this vehicle for a while so did the excessive consumption start recently? What has been the history of consumption during the time you've operated the vehicle?
 

tiredguy

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I've operated my old 1MZ-FE for 22 years and nearly 450,000 miles now. If you are consuming one quart per 500 miles then your choice of grade is the least of your worries.

Open up the rear cylinder bank as you've described. If there is a problem with sludge it will be there. Until you do that nothing anyone on here says makes no difference, assess the situation and move from there.

You say you've had this vehicle for a while so did the excessive consumption start recently? What has been the history of consumption during the time you've operated the vehicle
 
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Yeah the 1MZ is a really difficult engine! Pulling the valve covers is almost impossible, even worse on the RX300. Use iridium spark plugs along with new valve cover gaskets.

This is one of the few engines that requires synthetic and a 3k OCI.

Nothing wrong with 5w30 or 10w30. They also make HM synthetics, too. If you pull the valve cover and replace the gaskets, then it won't leak :)
 
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Supertech Advanced Synthetic 5w30 or 10w30, and ride on with 3000 mile intervals. I bet it will be a non-engine related failure that will "finish" the car.
 
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Well, you’re a better person than me...if I had a 21 year old car with 310,000 miles on it and it started drinking a quart of oil every 500 miles, I’d send it to the junkyard or donate it to my local vocational automotive program. And then I’d raise my glass and celebrate that I made it that far and sent it to a good home.
 
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Very important, please read this post.

Don't give up on fixing the oil consumption. These engines can consume oil because of the faulty design of the rear valve cover and PCV system. There is plenty of online documentation showing your model having severe oil consumption issues, which have been slowed or completely fixed by upgrading the rear valve cover and new style of PCV valve. If you are going to have the rear cover off for any reason, it's worth installing the updated one while already working back there. I have the same engine, and will be upgrading my rear valve cover next time I change the spark plugs and cover gasket.

Here is just one of many threads of people with crazy consumption going to little or no consumption after upgrading the valve cover and PCV valve+hose. https://www.clublexus.com/forums/rx-1st-gen-1999-2003/582802-reengineered-rear-valve-cover.html

RX300VC3.jpg


Link to the 3rd gen updated valve cover.
 
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